1. Field of the Invention
This invention relates to a method of and an apparatus for manufacturing a liner which is formed of non-woven fabric and is incorporated in a casing of a magnetic disk for protection and cleaning of the magnetic disk.
2. Description of the Prior Art
Conventionally, the liner for the magnetic disk is formed by stamping a sheet of non-woven fabric or a plurality of stacked sheets of non-woven fabrics to shape using contoured dies. However the conventional method using the contoured dies is disadvantageous in the following points. That is, contoured dies are generally inherently complex in shape and accordingly are difficult to form with high accuracy. At the same time, the non-woven fabric from which the liner is stamped out is generally of rayon, polyethylene terephthalate or the like which has poor processability, and the complexly contoured dies soon become blunted. Accordingly, in the case that a single sheet of non-woven fabric is stamped into a liner, there is too much wear of the dies relative to the number of liners to be manufactured, while stamping a plurality of stacked sheets of non-woven fabric into liners is very difficult and requires manual separation of the formed liners. Further, when the liner is stamped out from a sheet or sheets of the non-woven fabric by the contoured dies, each sheet of non-woven fabric must be larger than the liner to be formed, and accordingly the yield rate of the material is low.
On the other hand, if the non-woven fabric is stamped into the final shape of the liner in a plurality of stamping steps, the number of the dies is increased, adding to the manufacturing cost of the liner.